High-speed data communication systems are known to include current-mode driver amplifiers (drivers) and receivers. For best speed performance, the drive current should be calibrated. Such calibration should account for process variations, and is preferably repeated as needed to compensate for changes due to supply-voltage and temperature fluctuations.
Supply-voltage and temperature fluctuations occur during device operation, so driver recalibration is often desired of active (transmitting) drivers. Unfortunately, driver recalibration can introduce noise, and so is typically carried out on inactive drivers. Recalibration schemes either interrupt transmission or await a time when the driver is inactive. A better solution would allow for recalibration of active drivers without interrupting data transmission or introducing noise.